01 - Preheat your oven to 375°F. Line a baking sheet with parchment paper or foil.
02 - In a mixing bowl, combine cream cheese, mayonnaise, Dijon mustard, lemon juice, Worcestershire sauce, shallot, celery, parsley, Old Bay, garlic powder, black pepper, and salt. Mix until smooth and fully incorporated.
03 - Gently fold in the crab meat and chopped shrimp until evenly distributed throughout the filling mixture, being careful not to break up the crab lumps.
04 - Using a sharp knife, cut a horizontal pocket lengthwise into the side of each salmon fillet, cutting about three-quarters of the way through without piercing the opposite side.
05 - Generously fill each salmon pocket with the seafood mixture, pressing lightly to ensure the filling reaches the back of the pocket without overflowing.
06 - Place the stuffed fillets onto the prepared baking sheet. Brush the tops with melted butter and sprinkle evenly with Parmesan cheese.
07 - Bake for 20 to 25 minutes until the salmon is opaque throughout and flakes easily with a fork, and the filling is hot and lightly golden on top.
08 - Remove from oven and garnish with fresh lemon wedges and additional parsley if desired. Serve immediately while hot.